Metal fuselage



March 1s, 1930. E. B. CARNS i 1,750,834

METAL FUSELAGE Filed April 2, 1929 2 Sheets-Sheet l l 3513 Mis @lf/tome@ March 18, 1930. E, B, CARNS 1,750,834

METAL FUSELAGE Filed April 2, 1929 2 SheebS-SheeI -2 329% s @Hom/w13 WWW Patentea Mar. 1s, 1930 i UNITED s'riyrEs vn n/750,834-

PATENT OFFICE EDMUND IB. CARNS, NEW YORK, N. Y., ASSI-GNOR T0 CAIRNS DEVELOPMENT COM- PANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE METAL FUSELAGE Application filed April 2,

My invention relates to improvements in -metal fuselage construction for airplanes.A

More .particularly this invention pertains to an improvement of the structure disclosed in application, Serial No. 17 3,086, filed May 5, 1927, for metal fuselage or body. In common with the best practice in this art the object of my invention Iis/to produce a fuselage which can be economically made and assembled whichwill be as light as possibly consistent with the requisite strength, and which will offer the least air resistance. In attaining this object I employ three important factors:

A. The peculiar characteristics of these sheets;

B. The distribution of metal in the sheets lwhich compose the fuselage; and

this invention is the characteristics of the metallic sheets from which the fuselage is formed. I shape these sheets in what I call compound curves for convenience of terminology, that is, curved sheets, which if sectionsare taken at any point would disclose arcs curving continuous inwardly.

The sheets are given a curvature along a transverse line by passing them between convex and concave rolls which are recessed. These rolls bear with a certain pressure upon. the metal sheet. They may be either frictionally dniven by the action of the sheet being pulled throu h them, or may be given a direct ldrive of t e same or slower or circumferential speed as. the speed at which the sheet is pulled through. The metal sheet itself may be pulled through the rollers by any conventional means. While the sheet is being pulled throu h the rollers another force is brought into p ay upon the sheet, and it is this force that imparts the compound curvature and tension to the sheet. This force is directed on to the sheet by causing a movement of the rolls in an upward or downward direction to the direction of pull upon the sheet. This movement when combined with the transverse curve being given to the sheet and the longitudinal pull thereon, dis- .torts the sheet along its center line and in 1929. Serial No. 351,870.'

each of its edges, with the result that the sheet is given a longitudinal curvature. The operation and movement of the rolls may be controlled in such a manner that the sheet can be given a curve having radii which intersectat a point, or a curve having variable radii like the curve of a parabola. The sheet may also be given curves which blend from one form of curve into another.

As a result of having the sheet in compound curvature and as a result of the method of making in which the molecules of the metal are distorted in position, the entire fibre of the curved sheet is under tension. The result is that the sheet because of this tension is extremely sti, more rigid and quick in its reaction against the effect of `a blow or pressure which might otherwise .cause the sheet to become bent or distorted.

Due to these particular qualit-ies the sheets arev especially' valuable in construction where a strong yet light structure is desired, for it can be seen that veryvv little reinforcing` is necessary inasmuch as the sheets after'trimming are already formed to the shape desired. It is unnecessary to bend and t them in shape to structural members or to hold them in place-by the same. Further the curved sheets already ,have unusual strength due to their inherent tension, their compound curvature, and the l,fact that they are preformed. j

B. Theymetal sheets which I forin into the compoundcurved sheets described above may be formed of sheets of constant thickness, but I prefer to have the sheets of a tapering gauge, that is, to have the sheets tapered in thickness from the wider parts exposed -to greater strain, towards the narrower parts where there is less strain and so less metal required.

C. As to the shape of the structure, it is given a preferred stream-line outline. My invention gives to the surface a smoothcontour which offers very little resistance to theone sheet forming an entire side.

on small structures it is possible to have On the other'hand, on large structures it is possible by properly forming the sheets to fit and fasten them together and still maintain the compound curvature over the whole surface.

A preferred structure would be a fuselage having in a general way three sides formed. of compound curved sheets o'f the type described above. Such a structure is totally different from a triangular structure in which the sides lare formed by placing a covering over a frame, for as described above, my compound curved sheets are already preformed. They are not bent into place over the braces which would give an arc of a polygon having Va large radius as is the case in prior construction. On the contrary the compound curved sheets give continuous curves andv have'inherent in them a sufficient amount of strength, rigidity and stiffness to require very little bracing. Should a cross section be taken of a fuselage as de-A described above, it would give a generally triangular figure. lVhat it is, however, is a circular triangle and in which the radii of the arcs would intersect. It should be realized that such a cross section is inherent in the use of compound curved sheets.

Further objects and benefits of the invention will appear from the following description and accompanying -drawings in which like reference characters denote like parts throughout the several views.

hFigure 1 is a perspective View of a tapered s eet;

Ficure2 is a perspective view of a compoun curved tapered side of a fuselage;

Figure 3 is a perspective an'd diagrammatic view of Figure 2;

Figure 4 is a perspective View of a fuselage;

Figure 5 is a perspective View showing a sectional side; y

-Figure 6 is a longitudinal cross section of my fuselage; and

Figure 7 is a modified form of my fuselage.

Referring more particularly to the drawings, v

Figure 1 shows a sheet which is tapered in gauge in both directions from a middle portion. f.

Reference character 10 denotes the thicker section tapering at both yends to a narrow gauge as shown at 11. IThe tapering of `the thicknessV of the metal has been exaggerated in order to make it more apparent.

Figure 2 is a perspective view 'of a side of a fuselage made from a sheet as shown at Fig! ure 1 by imparting to it the compound curve and peculiar properties by a method such ashas been described above.

After the sheet of Figure l has been drawn to the compound curve described above, it

`may be trimmed to the desi-red shape giving the side sheet as shown in Figure 2.

Figure 3 is a perspective view of the sheets similar to Figure 2 with a diagrammatic representation which brings out the inherent curvatures of the sheet. The diagrammatic figures as designated by reference characters 12 are not intended to show ribs or bracing ina fuselage, but rather show the compound lcurvature of the sides of a fuselage and also triangular braces. It should be appreciated that not only are the circular triangular sections present at all points, but that the fuselage is continuously curved longitudinally, these curves merging with the circular triangle giving a member having locked stresses and thus great strength and rigidity.

The structural advantages in having circular triangular cross sections at all points in the fuselage are obvious. By my method a fuselage which is extremely rigid, strong,

light and yet having a great resistance to sudden stresses, is obtained.

Figure 4 shows a perspective view of my fuselage.l Any conventional method of fastening the side sheets together may be used. I have shown at 22 a preferred method in which I overlap the sides of the sheets.

These then may be held together by riveting or welding.

1n Figure 5 I have shown another method of forming my tapered side sheets in which the sections 16 and 17 may be Worked on separately by the method described above imparting to them the compound curvature and other properties. They may then be fitted and fastened together giving a sheet similar to that shown in Figure 2. These sections 16 and 17 may be made from sheets Which taper in thickness'in one direction only and for this reason it may be that such sheets will be easier to work. The thickest part of the metal would be at 17 a tapering in gauge to the thin portion at 17". The sheets should be formed to arcs of the same compound curves so that when they are fitted togetherthey will form continuous compound curves. This method is especially applicable when large fuselages are being constructed. It is,'of course, possible to form the sheets and fit them together longitudinally in making a large side section as well as transversely as disclosed in Figure 5.

Figure 6 is a longitudinal cross section of ymy fuselage disclosingthe tapering of the metal. At the point where' the greatest;vl

l fications.

, thickness to depart from'my invention. H Such a widening" stresses are incurred themetal is the thickest `transversely arched,` the` Sides beingover-pv I -as shown at 18,*Whereas'at those points at lapped' at the edges and' secured together,

which very 'littlefstress is brought to bear along the-over1a'p,suchoverlapped portions upon the fuselage', the metalhas tapered to a. forming longitudiiiallyv extending stiiening give'suiicient strength at that ribs.' c 1 1 i f n point asshown at 19. i f In testimony Whereof,'I`have signedlmy- In Figure 7 I have disclose`d a Lmodified -name .to this a gusset 20 in the upper section, 'Ihis'modi-y cation or other similar modifications do not'i,

of the fuselage may be necessary in Aadapting Y `the fuselage to certain types of motors or to' ,j

a certain cabin varrangement and the like. v The method of making and the type of my structurel have shown in a generally simplifi' lied manner. To those Whoare skilledl in the art it is obvious thatythere are many modi- It is obvious, for example, v,that my structure is jespeciallyapplicable to boat or pontoon construction, inasmuch as itfhas many characteristics in common with fuse# lage constructio Much less bracing would be needed and :a lighter, stronger and bmore easily7 manufactured boat would result fron l'. using my type of structure. I -therefore do not wish to be limited by my specication and drawings,'but onlyfbyl the prior art and the appended claims. Iclaim:' l. A fuselage for aircraft, substantially triangular in cross section and made of three l f n) preformed sidesl tapering in vwall thickness arched, such arched assembly of the three from a section of maximum stress to a section of minimum stress, each side having a convexr curvature from one end to the other and lhaving a continuous convex transverse curv-v l aturel atall points along its length, whereby each side is longitudinally and transversely, n

'substantially rigid in allvdimen-` sions.l

2. An 'elongatedb metal body, adapted for yuse as a fuselage for aircraft, substantially triangular in cross section andl made of three preformed sides taperingiin W'all thickness from a section of'maximum stress' to a section'- of minimum stress, each side-,having a convex curvature from one 'end to the other and having a continuous convex transversejcurvatureat'all points along its length, 'whereby each side is longitudinally L fand. .transversely arched, such arched assembly. of th'e'three sides being substantially rigid in 'all'dimen sions, and means connecting the longitudinal l marginal portions ofthe sides.

3. An elongated metal body, adapted for use as a fuselage, for aircraft, substantially triangular in cross section and made of three preformedl sid'es" .tapering in Wall thickness l from a section of maximum stress to a section' of minimum stress, eachnside being preformed convexly at all pointsl'ongitudinally and c on-` Vexly at all pointstransverselyof the fusem l lage whereby each sideis longitudinally and l specification this 28th dayfof vform of my fuselage in which I have inserted March,'1v929. f f 

